Reynolds stress may be defined as thea)Stresses (normal and tangential...
Ans. (c) Reynolds stress may be defined as additional shear stresses due to fluctuating velocity components in a turbulent flow.
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Reynolds stress may be defined as thea)Stresses (normal and tangential...
**Reynolds Stress: Definition and Explanation**
The Reynolds stress is a term used in fluid mechanics to describe the additional shear stresses that arise due to fluctuating velocity components in a turbulent flow. It is an important concept in understanding the behavior of turbulent flows and is named after Osborne Reynolds, a prominent physicist and engineer.
**Definition of Reynolds Stress**
The Reynolds stress can be defined as the additional shear stresses that exist in a turbulent flow field due to the fluctuating velocity components. These fluctuating velocity components are characteristic of turbulent flows and are responsible for the chaotic and unpredictable nature of such flows.
**Explanation of Option C**
Option C states that Reynolds stress is the additional shear stresses due to fluctuating velocity components in a turbulent flow. This is the correct definition of Reynolds stress.
**Additional Shear Stresses**
In a laminar flow, the shear stresses are primarily determined by the viscosity of the fluid. However, in a turbulent flow, the velocity of the fluid varies chaotically in both space and time. This leads to the generation of additional shear stresses, known as Reynolds stresses, which are not present in laminar flows.
**Fluctuating Velocity Components**
The fluctuating velocity components in a turbulent flow refer to the random and unsteady variations in the velocity of the fluid. These variations occur at different spatial locations and at different points in time. The fluctuating velocity components are responsible for the formation of eddies, vortices, and other turbulent structures in the flow.
**Importance of Reynolds Stress**
Understanding and quantifying the Reynolds stress is crucial for predicting and analyzing turbulent flows. The Reynolds stress affects the momentum transfer and energy dissipation in the flow, and it plays a significant role in various engineering applications, such as aerodynamics, heat transfer, and fluid flow control.
**Conclusion**
In summary, Reynolds stress is the additional shear stresses that arise due to fluctuating velocity components in a turbulent flow. It is an important concept in fluid mechanics and plays a crucial role in understanding and predicting the behavior of turbulent flows.
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